Exhaust leak

[investig8]

Hello all,
I have owned my M-37 (Fiona) for 5 years and have been plagued by an exhaust leak. I had the exhaust manifold machined and replaced all the studs about 3-years ago. I used the washers and nuts purchased from Vintage Powerwagons and although when I hear it leaking, I can tighten the nuts and it will fix it, it only lasts a few months and begins to leak again near the rear of the engine. Any recommendations?
Thanks, as always,
Dennis

[Rdinatal]

I can tighten the nuts and it will fix it, it only lasts a few months and begins to leak again near the rear of the engine.

Hi Dennis, have you checked if the studs are pulling out of the head?